Add migration path for different detection and recognition models
As it stands currently, it is very cumbersome and onerous to migrate from 1 detection/recognition model to another when we have live customer data already.
This works easy enough for a new customer as all of their data will be at the detection/recognition model that you specify.
However, for existing customers, we will have existing facelists and persongroups already with data in it, and short of reprocessing ALL the face data, we don't really have a viable way to migrate to the new models.
